Patent GB-772680-A (GB)
Title: Improved exothermic vapor-phase processes
IPC: B01J8/18
Filed: 1954-11-26
Abstract: In carrying out an exothermic vapour-phase hydrocarbon reaction, the reactants are contacted in countercurrent flow with heatabsorbing solid particles which are rained down through grids arranged in the reaction zone.  Paraffins, olefins, or naphthenes may be partially oxidized to a product containing <PICT:0772680/IV(b)/1> <PICT:0772680/IV(b)/2> epoxides, cyclic ethers, aldehydes, acrolein and methanol. Paraffins may be dehydrogenated to olefins and naphtha fractions converted to products of higher octane number.  Octene-2 and cetane may be oxidized without complete combustion.  Other reactions referred to are chlorinations, oxidations using nitrogen tetroxide, decomposition of peroxides and hydroperoxides, sulphurizations such as reactions involving gaseous sulphur and hydrocarbons, reactions involving acetylene or other C2 to C16 aliphatic unsaturated hydrocarbons, and oxidation of alcohols, ketones, aldehydes, aliphatic amines, ethers, and esters.  The solids may be inert, e.g. sand, fused alumina, quartz, glass beads, or silicates; a suitable size is from 25 to 800 microns.  Catalytic or adsorptive solids, e.g. activated alumina or silica, may be used to effect isomerization, dehydration or dehydrogenation, or oxides may be used to generate oxygen; these solids may be diluted with inert solids.  As shown in Fig. 1, the solid is heated in a fluidized bed 1 by means of pipes 3 to a temperature of 280-350 DEG  C. and flows through standpipe 4 to reaction zone 6 where it falls freely, being uniformly dispersed by screens 8, e.g. of stainless steel wire mesh. The solid collects in dense bed 9 and passes through stripping zone 10, screw conveyer 12, and gas lift line 13 back to fluidized bed 1, being cooled to 280-350 DEG  C. at 26.  Hydrocarbon reactant enters at 16 and some of the oxygen or air at 15; additional oxygen enters at 17 and is supplied to spaced points along the reaction zone; the product leaves at 25.  In Fig. 3, the reaction is carried out in pressure vessel 30, hydrocarbon entering at 31 and being heated in fluidized bed 38, e.g. to 300-400 DEG  C.; oxygen or air is introduced through series of concentric perforated pipes 32, some of which may be submerged in the bed 38.  Product leaves via cyclone 35 and outlet 34A.  Solid flows from bed 38 via conduits 48 to fluidized bed 37 where it is cooled by coils 47, e.g. to 300 DEG  C.  Lift gas introduced at 42 conveys the solid through pipes 41 to the top of the vessel where it contacts deflectors 44 and drops through the reaction zone to bed 38, being dispersed by means of the pipes 32 which act as screens.  In the examples (a) n-heptane and (b) a naphtha are treated with oxygen in accordance with the invention to give a product comprising olefines and epoxides having mainly the same number of carbon atoms as the starting material; some formaldehyde, acetaldehyde, propionaldehyde, acrolein and methanol are obtained as by-products.ALSO:In carrying out an exothermic vapourphase reaction, the reactants are contacted in countercurrent flow with heat-absorbing solid particles which are rained down through grids arranged in the reaction zone.  Paraffins, olefins, or naphthenes may be partially oxidized to a product containing <PICT:0772680/III/1> <PICT:0772680/III/2> epoxides, cyclic ethers, aldehydes, acrolein, and methanol. Paraffins may be dehydrogenated to olefins and naphtha fractions converted to products of higher octane number.  Octene-2 and cetane may be oxidized without complete combustion.  Other reactions referred to are chlorinations, oxidations using nitrogen tetroxide, decomposition of peroxides and hydroperoxides, sulphurizations, reactions involving acetylene or other C2 to C16 aliphatic unsaturated hydrocarbons, and oxidation of alcohols, ketones, aldehydes, aliphatic amines, ethers, and esters.  The solids may be inert, e.g. sand, fused alumina, quartz, glass beads, or silicates; a suitable size is from 25 to 800 microns.  Catalytic or adsorptive solids, e.g. activated alumina or silica, may be used to effect isomerization, dehydration, or dehydrogenation, or oxides may be used to generate oxygen; these solids may be diluted with inert solids.  As shown in Fig. 1, the solid is heated in a fluidized bed 1 by means of pipes 3 to a temperature of 280 DEG -350 DEG C. and flows through standpipe 4 to reaction zone 6 where it falls freely, being uniformly dispersed by screens 8, e.g. of stainless steel wire mesh. The solid collects in dense bed 9 and passes through stripping zone 10, screw conveyer 12, and gas lift line 13 back to fluidized bed 1, being cooled to 280 DEG -350 DEG C. at 26.  Hydrocarbon reactant enters at 16 and some of the oxygen or air at 15; additional oxygen enters at 17 and is supplied to spaced points along the reaction zone; the product leaves at 25.  In Fig. 3 the reaction is carried out in pressure vessel 30, hydrocarbon entering at 31 and being heated in fluidized bed 38, e.g. to 300 DEG -400 DEG C.; oxygen or air is introduced through series of concentric perforated pipes 32, some of which may be submerged in the bed 38.  Product leaves via cyclone 35 and outlet 34A.  Solid flows from bed 38 via conduits 48 to fluidized bed 37 where it is cooled by coils 47, e.g. to 300 DEG C.  Lift gas introduced at 42 conveys the solid through pipes 41 to the top of the vessel where it contacts deflectors 44 and drops through the reaction zone to bed 38, being dispersed by means of the pipes 32 which act as screens.